John Bell Hatcher was an American paleontologist and fossil hunter known as the "king of collectors" and best known for discovering Torosaurus and Triceratops, two genera of dinosaurs described by Othniel Charles Marsh. He was part of a new, professional middle class in American science, having financed his education with his labor while also being more educated than older fossil collectors. As such, he faced unique challenges throughout his long and productive career.

Torosaurus is a genus of herbivorous chasmosaurine ceratopsian dinosaur that lived during the late Maastrichtian age of the Late Cretaceous period, between 68 and 66 million years ago, though it is possible that the species range might extend to as far back as 69 million years ago. Fossils have been discovered across the Western Interior of North America, from as far north as Saskatchewan to as far south as Texas.